How to change HTTP port in Oracle FMW 11g

Changing the HTTP port in Oracle FMW 11g

The Oracle FMW OHS defaults to port 8888. But this may be changed to a custom port (to port 80 for example in order to keep the url simple). The actual port change is in the Oracle FMW Administrators Guide for Oracle HTTP Server, however this does not seem to cover promoting the port change to the em agent. If the em agent is not updated then you may experience an error similar to the following:

Note:
If you change the port or make other changes that affect the URL, such as changing the hostname, enabling or disabling SSL, you need to re-register partner applications with the SSO server using the new URL.